Look at the acidity of the Atlantic Ocean (map from the INTERNET). There are fewer rorals in the Atlantic. This is the answer to your question.

you can see my discussion "Why does the Atlantic Ocean have the smallest area of coral reefs?"

Dr Borys Kapochkin thank you for your contribution to the discussion

Ocean acidification slows the rate at which coral reefs generate calcium carbonate, thus slowing the growth of coral skeletons. Climate change can cause sea level rise; changes in the frequency, intensity, and distribution of tropical storms; and altered ocean circulation. Ocean acidification slows the rate at which coral reefs generate calcium carbonate, thus slowing the growth of coral skeletons. Greenhouse gas emissions are the main cause of ocean acidification and the increases in sea temperature that cause coral bleaching. Any efforts to reduce emissions will bring benefits both on land and at sea. Alongside threatened tropical coral reefs, cold-water corals are some of the most vulnerable species when it comes to anthropogenic carbon dioxide emissions. By reducing the growth potential and survivorship of corals, ocean warming and acidification are likely to change the competitive hierarchy of corals and macroalgae – at least indirectly by reducing the ability of corals to maintain or rapidly colonize available space following disturbances. Ocean acidification reduces the amount of carbonate, a key building block in seawater. This makes it more difficult for marine organisms, such as coral and some plankton, to form their shells and skeletons, and existing shells may begin to dissolve. However, as ocean acidification increases, available carbonate ions (CO32-) bond with excess hydrogen, resulting in fewer carbonate ions available for calcifying organisms to build and maintain their shells, skeletons, and other calcium carbonate structures. Rising water temperatures, acidification, and low oxygen levels can combine with natural ocean cycles to create extreme marine events. Marine heat waves, dead zones, and coral bleaching are just a few examples of these events, which are projected to become more common and severe. For good reason, ocean acidification is sometimes called “osteoporosis of the sea.” Ocean acidification can create conditions that eat away at the minerals used by oysters, clams, lobsters, shrimp, coral reefs, and other marine life to build their shells and skeletons. Human health is also a concern. Climate change leads to: A warming ocean: causes thermal stress that contributes to coral bleaching and infectious disease. Sea level rise: may lead to increases in sedimentation for reefs located near land-based sources of sediment.